The present invention relates to an improved pedal device suited for use in electronic musical instruments, such as electronic keyboard instruments, and an electronic musical instrument including such an improved pedal device.
In acoustic pianos that are among natural keyboard instruments, and particularly in grand pianos, as a human player steps on or depresses a damper pedal through a great stroke length, depressing force is transmitted to dampers via connection portions so that the dampers, so far held in contact with strings, start to be lifted upward away from the strings. At that time, a variation rate of reactive force increases due to, among other things, increase in frictional force caused by a resilient element of the entire connection portion and non-uniformity of movement between adjoining dampers. Thus, the human player feels that the variation rate of reactive force received from the damper pedal is changing in accordance with a depressed depth (stroke) of the damper pedal.
Hence, there has been known a technique which, in a pedal device of an electronic keyboard instrument, changes the variation rate of reactive force, received from the damper pedal, in accordance with a stroke length of the damper pedal, as disclosed in Japanese Patent Application Laid-open Publication No. 2004-334008 (hereinafter referred to as “the relevant patent literature”). The known technique disclosed in the relevant patent literature is arranged to cause two spring members to act progressively on the damper pedal. With this technique, it is possible to obtain a characteristic that the reactive force starts increasing midway through the entire stroke length in response to depressing operation of the pedal.
Another example of the construction for progressively changing the reactive force to the pedal of the electronic keyboard instrument is known, which includes, in place of the aforementioned springs, a reactive force imparting member for imparting reactive force to the pedal by being pressed by the pedal depressed by a human player. Such a reactive force imparting member is, for example, in the form of a one-piece member integrally formed of rubber or resilient synthetic resin material and having a generally upwardly-convexed hollow dome shape, and it is disposed in such a manner as to start being pressed by the pedal at a position midway through the pedal stroke. The reactive force imparting member includes a flat plate-shaped base portion, a generally cylindrical body portion formed on the upper surface of the base portion, and an abutting portion provided centrally on an upper end portion of the body portion. The abutting portion descends by being abutted against and pressed downward by the lower end surface of the pedal being depressed, so that the body portion resiliently deforms to produce reactive force to the depressing force applied to the pedal.
Examples of the aforementioned pedal that presses the dome-shaped reactive force imparting member include one having a downwardly-opening, inverted-U sectional shape defined by an upper wall and opposed side walls extending downward from the opposite side edges of the upper wall. In mounting the dome-shaped reactive force imparting member under the lower surface of the pedal, it is necessary to appropriately set a mounted position of the reactive force imparting member relative to an initial (undepressed) position of the pedal with a stroke length of the pedal taken into consideration. Therefore, a gap that is greater than the pedal stroke length when the pedal is in the initial position is provided between the lower ends of the opposed side walls and the reactive force imparting member. However, because the gap is greater in size than a width of a finger of a person, a finger or the like might be caught between the lower end of the pedal and the reactive force imparting member when the pedal is depressed from the initial position. Thus, there has been a need for further measures to secure sufficient safety of the pedal device.
Further, to secure the stroke length of the pedal, the dome-shaped reactive force imparting member has to be mounted spaced downwardly from the initial position of the pedal. Thus, as viewed from above the pedal, the reactive force imparting member is not completely hidden under the pedal so that a part of the reactive force imparting member may be undesirably seen from the human player. Thus, the human player may be given an uncomfortable feeling due to a difference from the pedal device of the acoustic piano.
Furthermore, in the case where the reactive force imparting member is mounted spaced downwardly from the initial position of the pedal as noted above, the lower surface of the pedal and the abutting portion of the reactive force imparting member would be greatly spaced from each other. In such a case, the abutting portion of the reactive force imparting member cannot be pressed directly by the lower surface of the pedal, and thus, a separate member (i.e., actuator) for pressing a key top portion has to be provided on or adjacent to the lower surface of the pedal. As a consequence, there arises the problem that the number of component parts for constituting the pedal device increases.